1. Field of the Invention
The present invention relates in general to a device for manipulating a stylet for positioning an electrode cable in a body cavity, such as a human heart. More particularly, the present invention relates to a device for manipulating a stylet unit of the type having a stylet sleeve and a guide wire located within the sleeve. The distal end portion of the inner guide wire is pre-shaped into a curved configuration so that when it is freely exposed from the distal end portion of the associated flexible, but stiffer stylet sleeve by performing a relative displacement between the latter and the guide wire, the free distal end portion of the guide wire will be capable of bending the distal end portion of the electrode cable into a desired curved shape. In this manner, the tip of the electrode cable may be bent between a substantially straight configuration to a substantially J-shaped configuration in order to locate and fixate the tip of the electrode cable at a suitable site in the heart.
2. Description of the Prior Art
U.S. Pat. No. 5,170,787 discloses a device for manipulating a stylet unit of the kind referred to above for in vivo positioning of an electrode cable. This known device has a handle having a first handle member and a second handle member attached to one another for mutual movements thereof, one of the handle members being connected to a proximal end portion of one of the stylet sleeve and guide wire, the other of said handle members being connected to a proximal end portion of the other of the stylet sleeve and guide wire. This device further has means attached to a distal end portion of one of the first and second handle members for fixation of a proximal contact element of the electrode cable to that one of the first and second handle members. Such a prior art device normally operates smoothly and flawlessly with electrode cables having substantially the same length of the central lumen into which the stylet unit is to be inserted. Thus, in order to obtain proper function of the device, e.g. to ensure accurate control of the electrode tip while positioning the same in e.g. a heart, it is important that the distal tip of the guide wire always reaches the bottom end of the lumen, while the proximal contact element of the electrode cable is fixated to its associated handle member of the device. Although the overall outer length of the electrode cables may be substantially identical, the length of their inner central lumen may vary in dependence of the actual electrode tip design being used, e.g. active (screw-in) or passive fixation (fins or tines). Also manufacturing tolerances of some models of the electrode cables may vary within the range xc2x11.3 cm. In the preferred embodiment of the stylet manipulating device of U.S. Pat. No. 5,170,787, the distance between the distal end of the guide wire and the point of fixation of the proximal element of the electrode cable to the associated one of the handle members should be a fixed distance, i.e. the associated handle member should be a stationary handle member to which the guide wire is attached, and the other handle member should be a displaceable handle member to which the stylet sleeve is attached. Such a known fixed length-manipulating device therefore is not suitable for accurate handling of the tip of the electrode cables having various lengths of the lumen thereof.
In order to modify existing stylet manipulating devices of the above-mentioned type so as to accommodate lumen length variations and manufacturing tolerances, it has been suggested (see xe2x80x9c846/Research Disclosure. July 1998, publication 41106xe2x80x9d) to provide a set of adapters of various lengths (FIGS. 2 and 3) which are detachably mountable to one and the same handle unit. These adapters are made to fit various predetermined electrode lumen lengths. Furthermore, FIG. 4 of this publication xe2x80x9c41106xe2x80x9d indicates the use of a telescopic adapter assembly to accommodate lumen length variations by means of one single handle/stylet unit. Such a telescopic assembly requires rather complicated and expensive structural means in order to obtain accurate and stable length adjustments and to prevent mutual rotation of the telescopic elements.
It is an object of the present invention to eliminate the aforementioned short-comings of the prior art devices and to provide a simplified stylet manipulating device, which has one single stylet/handle unit which can be used for manipulations of electrode cables having various lumen lengths.
The above object is achieved in accordance with the principles of the present invention in a device for manipulating a stylet unit wherein the stylet unit has a stylet sleeve and a guide wire located in the sleeve, the device having a handle with a first handle member and a second handle member attached to each other for movement relative to each other, one of said handle members being connected to a proximal end of one of the stylet sleeve and guide wire, and the other of the handle members being connected to a proximal end of the other of the stylet sleeve and guide wire, a fixation arrangement attached to a distal end of one of the first and second handle members for fixing a proximal contact element of the electrode cable to the handle member to which it is attached, the fixation arrangement being displaceably mounted relative to the handle member to which it is attached so as to be adjustable to accommodate variations in length of a central elongated lumen of the electrode cable into which the stylet unit is to be inserted, and wherein the fixation arrangement has a slide member slidably mounted in a single bracket member having a proximal base portion rotatably attached to the handle member to which the fixation element is attached, and a distal shaft portion with a guide track for the slide member, the slide member carrying a locking mechanism for securing the proximal contact element of the electrode cable to the slide member.